In 3GPP GSM/UMTS/LTE wireless access systems, a mode of networking using a distributed building Base Band Unit (BBU) and a RRU has been very popular in terms of application. The band IQ data is transmitted between the BBU and the RRU. The transmission rate of the band IQ data is required to be 1.2288 Gbps or 2.4576 Gbps, which depends on the carrier capacity. In order to meet the high transmission rate of the band IQ data, the optical fiber or the microwave device with high frequency and wide bandwidth is currently utilized in the art. Both of the transmission methods, however, require the operator to re-lay the optical fiber or the microwave transmission network, thereby resulting in the high cost of the network deployment.